Editor’s note: This article is based on the presentation “Integrating Feral Hog Management into your Wildlife Management Program” by Michael Botha, president, Sandwich Isle Pest Solutions, Pearl City, Hawaii, at NPMA PestWorld 2014.
Wild pigs (Sus scrofa), also known as wild hogs, wild boars or feral swine, are an Old World species not native to the Americas. They were brought here by early settlers and explorers, including Spanish explorer Hernando DeSoto, who introduced hogs in the Southeast in the 1500s in the hopes that upon his return there would be ample feral hogs to harvest. (Mission accomplished.) Later, Eurasian boars were introduced for hunting purposes. In modern times, free-range livestock management practices and escapees from enclosures have resulted in expanding populations of wild pigs. Domestic pigs can directly move into a herd of feral pigs.
Feral pigs, often found near water to accommodate their love of wallowing, have been reported in at least 45 states, with the largest populations in Texas through Florida, the Southeast, California and Hawaii. Their range has grown as far north as Michigan, North Dakota and Oregon. “Where you find wolves there aren’t many, if any, pigs, including Montana, Wyoming, Idaho and Utah,” explained Michael Botha, president, Sandwich Isle Pest Solutions, Pearl City, Hawaii. In the last 20 years, the expanding range of the estimated 4 million feral pigs in the United States is primarily the result of illegal translocation of pigs by humans, as well as the ongoing escape or release of domestic swine.
Feral pigs in Hawaii are descended from small, aggressive Asian domestic pigs that were brought by the Polynesians in the early colonization period, about 400 A.D. The larger European domestic pigs were introduced by Capt. James Cook in the late 1700s. Most of the existing feral pig populations in Hawaii have crossbred with domestic escapees.
They Eat Like Pigs.
Pigs are omnivores, eating both plant and animal matter. And they really do eat like pigs as a result of their simple stomach, which requires them to forage almost continuously because of their inefficient digestive system. Their widely varied diet contributes to their ability to thrive in a wide range of expanding environments. The majority of their diet consists of grasses, forbs (herbaceous flowering plants), shoots, roots, tubers, fruit and seeds.
They also eat a variety of invertebrates including earthworms, grasshoppers, centipedes, beetles and other arthropods. “Pigs are always foraging in moist areas searching for earthworms, their primary source of protein,” said Botha. As a predator, pigs eat frogs, fish, crabs, turtles, rodents, snakes, eggs and chicks of ground nesting birds and livestock. They’ve been known to kill immature goats.
The extensive, costly destruction caused by feral pigs is particularly troubling for Hawaii’s native habitats and agricultural crops.
“Feral pigs are the single worst ecological disaster of forests in Hawaii,” said Botha. These “rototillers of nature” are a destructive nuisance and devour vegetation, trample undergrowth, compact soil and uproot tender shoots of growing plants. They destroy soil structure when foraging for food. Rooting at the base of trees and shrubs can undermine root systems and weaken trees. Their wallowing habit also creates hollows in pristine native forests, which then collect the standing water needed by mosquitoes to breed, which has severely impacted the spread of avian malaria.
Their impact on agriculture has been devastating and has changed farming practices in Hawaii. Many farmers report severe damage to corn and other seed crops, making it necessary to fence 100 percent of their fields to protect crops. Fencing is effective, but costly. “I’ve seen pigs in grassy areas that in the span of an hour tear up a 20- by 20-foot area foraging for earthworms,” Botha said.
He continued: “They’ll walk up to a stalk of corn, knock it over, test a kernel for moisture and taste, then move on to the next and the next. In one case, 50 percent of a corn crop within a 40-acre area was destroyed in a weekend by only six feral pigs.
“Many residential and commercial areas abutting forested areas, even in highly populated regions, suffer significant feral pig damage to lawns and ornamental plantings,” said Botha. “Pigs rooting around plants looking for earthworms can severely damage expensive landscapes.”
“It’s been said that 70 percent of a feral pig population must be eliminated annually to maintain the population,” explained Botha. “Pigs have no natural predators. Without an aggressive management program they’ll continue to overrun the environment. We decided that our company would become the No. 1 predator of feral pigs in Hawaii.”
The management program developed by Sandwich Isle includes gated corral traps, which are used to capture entire sounders (a sow and piglets); box traps for individual pigs; and precision shooting (hunting). Thermal and night vision devices are used for observation and precision eradication.
Although used by some, the company does not use snares, which have limited success in capturing feral pigs, Botha said. In one study, 118 snares were placed over 10 hectares, which resulted in an average of 1.5 pigs per hectare being captured. Snares also are a cause for concern when the welfare of snared animals is considered.
Small-scale trapping is useful in populated areas, but only addresses individual pigs. Pigs are smart and those not trapped quickly learn to avoid the traps after only one negative experience, which makes future trapping difficult.
Hunting is most effective in easy access areas. Ground shooting is generally only effective on small, isolated, accessible populations. Shooting from helicopters is effective in inaccessible areas, but is controversial.
“We’ve found corral traps, with a remotely controlled gate to be the most effective method,” said Botha. “Using a corral trap, we’re able to capture entire sounders with the push of a button while we’re on-site or from a remote location while viewing live video or images sent to a mobile phone.”
Some patience is needed when using corral traps as feral pigs need to be trained to enter the trap over time. Timers are set to broadcast feed every day at the same time. Pigs become accustomed to the nightly meal and, eventually, the entire sounder returns daily.
Video and digital cameras capture footage and images of hogs entering the trap enclosure. By monitoring the live feeds, an operator can make an educated guess as to when the entire sounder has entered and remotely close the gate.
It’s critical to keep the corral trap clean. “Feral pigs never poop where they eat,” said Botha. “If a pig poops in the trap another pig won’t come into the trap to eat. So, if you don’t clean out the trap, you won’t get any other pigs to come in and feed.
“Trapping is the most efficient method for containing entire sounders in the shortest period of time,” said Botha. “We believe this is the best method because it requires the least amount of time, money and labor for a 100 percent or nearly 100 percent, capture.
“We also believe all creatures deserve to be treated as humanly as possible, which corral traps allow,” said Botha. Trapped feral pigs also have the right to an ethical kill — one shot to the head is typically sufficient.
If it looks like a pig and smells like a pig…
- Feral pigs are commonly black. You’ll also find red, brown and multicolored. Within only two generations out of captivity, domestic pigs usually lose their pink hue and turn striped and coarse-haired.
- They have heavy, stocky bodies with a dense coat of bristly hair.
- Mature boars have a thick shoulder shield of up to 3 inches — an inflexible cartilage, reminiscent of tire rubber.
- They have short legs, hooves, a straight tail and a long snout used for rooting.
- Feral pigs have been observed jumping as high as 60 inches when under stress.
- They have excellent hearing, poor eyesight and a great sense of smell. This explains the effectiveness of quietly approaching them head on from downwind.
- You’ll find dangerous tusks, which are technically canine teeth, on the lower jaw of both males and females.
- Mature pigs are 20-30 inches at the shoulder.
- Average weight: males, 150 pounds; females, 140 pounds.
- Lifespan: 8-12 years.
- Tooth decay and gum disease are a leading cause of natural death and contributes to their foul smell.
- Feral pigs are largely nocturnal.
- They can travel great distances — up to six miles in a night have been observed.
Handling Trapped Pigs.
“Never underestimate a feral pig. They’re like little bears,” said Botha. The aggressiveness and speed of feral pigs makes safety a priority when handling trapped feral pigs. “Pigs are really, really hard to keep contained. They’ll find a way out. I’ve seen stressed pigs escape over a 52-inch hog panel.”
Always carry a back-up gun and manage traps in pairs, Botha said. If your gun jams you have the opportunity for a second shot or the other hunter can take the shot. It’s also advisable to use an insurance shot after a pig is down. You can’t be too safe, he added
The most efficient method when approaching pigs in a trap or even open areas, is to walk straight toward the pigs from down wind. “If you steadily walk toward a pig they’ll just keep eating,” said Botha. “If you start moving sideways, like a dog, they’ll take off.” The same technique works when approaching a pig in the open. Always watch your back. Just assume there are other pigs in the immediate area.
Always use extreme caution when handling feral pigs to avoid being exposed to hog brucellosis, which in humans causes flu-like symptoms, is incurable and fatal. “There’s danger from field to freezer,” said Botha. Precautions include avoiding handling or cleaning pigs if you have cuts or sores on your hands, always wearing gloves (such as big game gut gloves), avoiding all contact with bodily fluids and the pigs’ reproductive organs and washing your hands immediately after you’ve finished handling pigs.
Cooking the meat thoroughly kills the bacteria, making the meat safe for consumption. “We donate 90 percent of the pigs killed to very eager recipients,” said Botha.
- Sex is the predominant drive in boars, taking precedence over food. (Could this be the origin of the phrase “men are pigs”?)
- Sows come into heat year-round in Hawaii.
- Gestation is 115 days — three months, three weeks and three days.
- Litters of 4-8 piglets are born in a ground nest build by the sow.
- The survival rate of piglets is high due to the absence of predators.
- Only a few days after birth, piglets follow the sow and begin eating solid food and are weaned at eight weeks, at which time they are referred to as shoats.
- Shoats can begin breeding at 6-8 months and as early as five months in Hawaii.
- Peak birthing in Hawaii coincides with the availability of food.
“There’s very little competition in managing feral pigs and the problem is increasing,” said Botha. “This is a great time to get into the business, because it’s a problem that will likely spread nationwide. Although, in some states the only legal entity that does hog control is USDA Wildlife Services, but they’ve had only limited success.
“Feral hog management is a great opportunity to provide a valuable service and grow recurring revenue,” said Botha. “Pest management companies that expand into wildlife management are providing a valuable solution to an increasing problem for farmers and homeowners.” Adding feral pig management is fairly easy for companies with an existing wildlife program. You’ll need a tough hunter and essential equipment. Hunter education, state licenses and gun safety training documentation all must be considered when creating any wildlife management program.
The social life of a pig
- All pigs are social and the life of a feral pig is no different.
- A sounder consists of a sow and her piglets.
- There are clearly defined roles and interactions among a sounder. The fight for dominance begins only days after birth. The pecking order is fixed for life.
- Boars tend to be loners, spending about 70 percent of their time alone, compared to sows, which spend more than that with their piglets.
Dan Austin is a Florida-based freelance writer.